[cheshirecheese]

I seem to remember my mother-in-law spraying her runner beans with a soapy water solution to get rid of blackfly.  Amazingly, we've not really suffered with them much ourselves in the past and have simply used the hosepipe on the few we've had.  However, I've just been to pick another lot of beans, and realised to my horror that pretty much every plant is infested with blackfly.  I tried using the hose, but it's hardly touched them.  Please could someone tell me the ratio of washing up liquid to water - and also whether any type of washing up liquid will do?  Many thanks 

[cheshirecheese]

... Just realised that sounded as though I was asking whether I should use Fairy Liquid or a cheaper own brand!  What I actually meant was, does it have to be something like eco-friendly Ecover.

[Hampshire Hog]

I have done this mainly for broad beans. For the proportions all I do is fill up a simple small sprayer and squirt in a little amount of fairy or similar. Although I have a science training I haven’t used a more technical measurement I’m afraid. And no I don’t use an eco product. HH

[jaydig]

Last year I arrived on the plot to discover that the swedes were absolutely infested with horrible grey aphids. The only thing I had in the shed was a container of handwash (necessary because of Covid), so I squirted a generous amount of this into my sprayer.  Not only did the plot smell lovely, but I never saw another aphid again.  It was only cheap handwash, but they didn't like it!

[JayG]

I aim to make it as dilute as possible whilst still doing the job, which is to penetrate the waxy coating of the blackfly so they look 'soggy', for want of a better word.

About 1 teaspoon of ordinary washing up liquid per pint (1 1/2tsp per litre) in a hand sprayer seems to be about right - it obviously helps to catch them early before they have developed into major colonies, and also before the ladybirds and their larvae arrive to hopefully do the job for you.

[rowlandwells]

although we haven't had a blackfly infestation this year on our runner beans we did have some on our broad beans so I picked the tops of and it seemed to do the trick without spraying

 I agree with JayG that is a good method using washing up liquid that's what I would do if we needed to get rid of the black fly if i remember my Dad used the same on his beans beans years ago with the washing up water and  it did the trick

i just wondered if we could try the same to spray  our brassicas adding some sugar to the mix that as I've been told it does control aphids as the sugar helps the adhesion but I've never ventured to try this method but got cold feet encase it doesn't work 

[Clactonite]

I have tried this old and trusted method for two years now...  one of my grandads had a large jar in the greenhouse which he would swirl gently every time he went into it.  The jar had a few bits of old soap at the bottom which were slowly dissolving into the liquid.  He'd pour some into a sprayer and dilute further.  Due to the nurseries and shops being closed during last Spring, I went back to this method of pest reduction.  WORKS A TREAT.  Try it on ants and the effect is immediate, also cabbage white butterfly caterpillars (takes longer).  An excellent green and blackfly pesticide and totally organic.

[cc]

Not sure if it's not an old wives tale. I removed all the black fly on sweet peppers by spraying them with water no soap in it. They simply fell of and drowned in the top of the plant pot.
The statement relates to blackfly only. Greenfly I squash with my finger and thumb on sweet peppers. Green fly starts on sweet peppers before moving on to tomatoes in my greenhouse.. So all I have to do is keep them under control on the sweet peppers and they won't move on.